It might be frustrating for you personally because you know so much that you could talk for hours about what happens, from keyboard interrupts to DNS to HTTP(s) and what-have-you, but in the absence of a personal recommendation, interviewers have to operate under the assumption that any and all claims of knowledge/experience/skill are suspect. I have interviewed people who claimed to have "deep algorithm design experience" who could not articulate what a set is, "network experts" who hadn't heard of NAT, and several "top graduates from a respected CS program" who froze when asked to talk about some basic tree operation.

If you'd responded to the question with the shocked response above, I'd probably have said "don't worry about it, let's pick X and Y" and mentally marked you as having knocked the question out of the park.

I can't stress enough how little the average applicant knows, regardless of how long they've been in the industry. It's helpful to have these questions as some sort of filter if you're looking to hire into a more-senior role, because many people either lie or obliviously overestimate their skills.

That said, if I was interviewing for a junior position and they bombed the question, I'd probably just make a mental note to buy them a copy of TCP/IP Illustrated when they came onboard or something.